Now, it's the toughest.

For the first time since the NCAA Tournament field expanded to 64 teams in 1985, the Tar Heels are in a region -- the East -- where all top four seeds advanced.

While No. 1 UNC plays No. 4 Washington State on Thursday at Charlotte Bobcats Arena in Charlotte and No. 2 Tennessee takes on No. 3 Louisville, the other three quadrants of the bracket saw upsets.

So in theory, the other No. 1 seeds -- UCLA, Kansas and Memphis -- have smoother paths to the Final Four in San Antonio.

It is unusual to have all four top seeds in a region still alive at this stage.

Since the tournament field expanded to 64, it has happened 10 times out of a possible 92.

Of those, consider this:

* Only once did the No. 1 seed from that "tough" region go on to win the national title: Duke in 1992.

* Only one other No. 1 seed made it to the national championship game: Georgetown, in 1985, which then lost to its Big East rival Villanova.

More commonplace has been the fate of top seed Kansas last year, which was in a West Regional final with the other top top seeds, won a game to make it to the final eight, then stumbled against second-seeded UCLA.

Indeed, since Duke's run in '92, five of the No. 1 seeds have faced the same situation as UNC does this year. It happened in a region in 1994, 1999, 2001, 2004 and 2007. In all of those years, the No. 1 seed did not advance to the Final Four.